Electron imaging of charge-separated field on a copper film induced by femtosecond laser irradiation

摘要

An instantaneous charge-separated field, built up at the femtosecond-laser-irradiated surface of a copper film, was observed by time-resolved electron imaging using an energy-chirped electron probe-beam. The probe beams with effective energies of 170 keV were generated by intense femtosecond laser irradiation onto a molybdenum target at an intensity of 10~(17) W/cm~2. From the deflection of the probe electrons, the electric field was estimated to be 1.5 MV/m at a pump-laser intensity of 10~(15) W/cm~2.